ETH Zurich researchers have developed several new components for biological circuits they say are important for constructing precisely functioning and programmable bio-computers. The researchers want to created small circuits made from biological material that can be integrated into cells to change their functions. The researchers developed a biological circuit that controls the activity of individual sensor components using an internal “timer.” The circuit prevents a sensor from being active when not required by the system. In the new biosensor, the gene responsible for the output signal is not active in its basic state because it is installed in the wrong orientation in the circuit DNA. “The input signals can be transmitted much more accurately than before thanks to the precise control over timing in the circuit,” says ETH Zurich professor Yaakov Benenson. The researchers also have developed a signal converter that changes one signal into another, and also can be used to convert multiple input signals into multiple output signals. Benenson says the technology will increase the number of applications for biological circuits. “The ability to combine biological components at will in a modular, plug-and-play fashion means that we now approach the stage when the concept of programming as we know it from software engineering can be applied to biological computers,” he says.